Sirio Vector 4000 SWR issue

[Hairball]

Have had the Vector up for about 1 year. Worked great with flat swr's. Checked swr's yesterday and almost 3 on channel 1 and 2.5 on 40. No idea why. Going to take down and check it out. Visually everything looks fine. Anyone with Vector experience have any ideas? Swapped coax with same results.
Thanks in advance,
Harry

 

[pienari]

Have you drilled water hole to gamma tube?.

 

[Hairball]

No I have not. Does it collect water?

 

[Shadetree Mechanic]

I had the set screw fall out and the egg beater slid down in the top section one time.

 

[Hairball]

Antenna down and backnup with loktite and lock washers. SWR 1.2 on 40 and flat on 1. No matter how much I tried I can't get ch40 any lower. When I use regular thin coax the swr are flat across the board. When I use the thicker "better" coax the swr's are 1.2. Both coax is same length. Any thoughts? Thank you.

 

[Dmans]

Antenna down and backnup with loktite and lock washers. SWR 1.2 on 40 and flat on 1. No matter how much I tried I can't get ch40 any lower. When I use regular thin coax the swr are flat across the board. When I use the thicker "better" coax the swr's are 1.2. Both coax is same length. Any thoughts? Thank you.

Use the larger coax (is it old and weathered?) and ignore the .1 difference. You will never hear the difference neither will anyone who is listening to your transmission.
Is the SWR meter you are using calibrated to a .1 resolution? Tried tuning it with a Nano VNA?

73
David

 

[ForestRunner98]

Antenna down and backnup with loktite and lock washers. SWR 1.2 on 40 and flat on 1. No matter how much I tried I can't get ch40 any lower. When I use regular thin coax the swr are flat across the board. When I use the thicker "better" coax the swr's are 1.2. Both coax is same length. Any thoughts? Thank you.

Call it a day and get to calling!!! Those are good numbers. Don’t get too hung up on the 1.1 match.

 

[pienari]

Can you tell gamma match lenght?.
Is it near to bottom when you get that result?.
Maybe you have to shorten top section to get lower swr on 27.405.
1:1.0 can be archived fine tuning.
I have tuned with antenna analyzer.

 

[M0GVZ]

Antenna down and backnup with loktite and lock washers. SWR 1.2 on 40 and flat on 1. No matter how much I tried I can't get ch40 any lower. When I use regular thin coax the swr are flat across the board. When I use the thicker "better" coax the swr's are 1.2. Both coax is same length. Any thoughts? Thank you.

"SWR makes you stupid."

My thoughts are don't bother trying to chase 1:1 SWR. Antennas that have a wide 1:1 SWR are generally lossy. The reason you get 1:1 SWR flat across the board when using thin coax is because of the losses in the coax.

As long as the SWR is no more than 1.6-1.8:1 across the channels you want to use then there's no advantage to chasing any lower than that. The 1.6-1.8:1 is the upper limit that PAs like to operate in and above that they'll start to fold back the power.

 

[Hairball]

Large coax is in great shape. Meters are Daiwa CN-901 and a friends Yaesu. Both read very close to each other. There is length both ways with the gamma match. I'm just going to enjoy the antenna and not worry about the swr. I certainly shouldn't worry about 1.2. Thank you all for your help.